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Final feedback implementation and fixes

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This commit is contained in:
Daniel
2020-09-24 22:03:02 +02:00
parent 67cdc52fcd
commit 89dfbf72e6
6 changed files with 84 additions and 55 deletions
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40
resolver/rrcache.go
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@@ -23,7 +23,7 @@ type RRCache struct {
Domain string // constant
Question dns.Type // constant
Answer []dns.RR // might be mixed
Answer []dns.RR // constant
Ns []dns.RR // constant
Extra []dns.RR // constant
TTL int64 // constant
@@ -34,6 +34,7 @@ type RRCache struct {
servedFromCache bool // mutable
requestingNew bool // mutable
isBackup bool // mutable
Filtered bool // mutable
FilteredEntries []string // mutable
@@ -55,19 +56,11 @@ func (rrCache *RRCache) ExpiresSoon() bool {
return rrCache.TTL <= time.Now().Unix()+refreshTTL
}
// MixAnswers randomizes the answer records to allow dumb clients (who only look at the first record) to reliably connect.
func (rrCache *RRCache) MixAnswers() {
// Clean sets all TTLs to 17 and sets cache expiry with specified minimum.
func (rrCache *RRCache) Clean(minExpires uint32) {
rrCache.Lock()
defer rrCache.Unlock()
for i := range rrCache.Answer {
j := rand.Intn(i + 1)
rrCache.Answer[i], rrCache.Answer[j] = rrCache.Answer[j], rrCache.Answer[i]
}
}
// Clean sets all TTLs to 17 and sets cache expiry with specified minimum.
func (rrCache *RRCache) Clean(minExpires uint32) {
var lowestTTL uint32 = 0xFFFFFFFF
var header *dns.RR_Header
@@ -221,6 +214,9 @@ func (rrCache *RRCache) Flags() string {
if rrCache.requestingNew {
s += "R"
}
if rrCache.isBackup {
s += "B"
}
if rrCache.Filtered {
s += "F"
}
@@ -253,6 +249,7 @@ func (rrCache *RRCache) ShallowCopy() *RRCache {
updated: rrCache.updated,
servedFromCache: rrCache.servedFromCache,
requestingNew: rrCache.requestingNew,
isBackup: rrCache.isBackup,
Filtered: rrCache.Filtered,
FilteredEntries: rrCache.FilteredEntries,
}
@@ -263,13 +260,23 @@ func (rrCache *RRCache) ReplyWithDNS(ctx context.Context, request *dns.Msg) *dns
// reply to query
reply := new(dns.Msg)
reply.SetRcode(request, dns.RcodeSuccess)
reply.Answer = rrCache.Answer
reply.Ns = rrCache.Ns
reply.Extra = rrCache.Extra
// Set NXDomain return code.
if rrCache.IsNXDomain() {
// Set NXDomain return code if not the reply has no answers.
reply.Rcode = dns.RcodeNameError
} else {
// Copy answers, as we randomize their order a little.
reply.Answer = make([]dns.RR, len(rrCache.Answer))
copy(reply.Answer, rrCache.Answer)
// Randomize the order of the answer records a little to allow dumb clients
// (who only look at the first record) to reliably connect.
for i := range reply.Answer {
j := rand.Intn(i + 1)
reply.Answer[i], reply.Answer[j] = reply.Answer[j], reply.Answer[i]
}
}
return reply
@@ -286,13 +293,16 @@ func (rrCache *RRCache) GetExtraRRs(ctx context.Context, query *dns.Msg) (extra
// Add expiry and cache information.
if rrCache.Expired() {
extra = addExtra(ctx, extra, fmt.Sprintf("record expired since %s, requesting new", time.Since(time.Unix(rrCache.TTL, 0))))
extra = addExtra(ctx, extra, fmt.Sprintf("record expired since %s", time.Since(time.Unix(rrCache.TTL, 0)).Round(time.Second)))
} else {
extra = addExtra(ctx, extra, fmt.Sprintf("record valid for %s", time.Until(time.Unix(rrCache.TTL, 0))))
extra = addExtra(ctx, extra, fmt.Sprintf("record valid for %s", time.Until(time.Unix(rrCache.TTL, 0)).Round(time.Second)))
}
if rrCache.requestingNew {
extra = addExtra(ctx, extra, "async request to refresh the cache has been started")
}
if rrCache.isBackup {
extra = addExtra(ctx, extra, "this record is served because a fresh request failed")
}
// Add information about filtered entries.
if rrCache.Filtered {